Wireless remote sensing power meter

ABSTRACT

A remote radio frequency (RF) power sensing unit including a first module and a second module. The first module may be configured to generate a digital output representative of a power level of a radio frequency (RF) signal. The second module may be configured to convert the digital output of the first module to a digital signal communicating the power level and transmit the digital signal communicating the power level over a wireless communication channel using a wireless protocol.

This application relates to U.S. Ser. No. 13/310,000, filed Dec. 2, 2011, which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the test and measurement field generally and, more particularly, to a method and/or architecture for a wireless remote sensing power meter.

BACKGROUND OF THE INVENTION

Power meters are used by maintenance engineers employed by major telecommunications companies. The current instrumentation market is mainly populated by stationary power meters designed for laboratory countertops, as well as portable power meters that tend to be rather large and bulky. Neither of these options proves to be convenient or practical for outdoor use by installation and maintenance engineers.

It would be desirable to implement a system that allows remote placement of monitors for measurement of power using a handheld device and that matches the level of accuracy of a countertop meter, but without being physically connected to the monitor.

SUMMARY OF THE INVENTION

The present invention concerns a remote radio frequency (RF) power sensing unit including a first module and a second module. The first module may be configured to generate a digital output representative of a power level of a radio frequency (RF) signal. The second module may be configured to convert the digital output of the first module to a digital signal communicating the power level and transmit the digital signal communicating the power level over a wireless communication channel using a wireless protocol.

The objects, features and advantages of the present invention include providing a wireless remote sensing power meter that may (i) allow remotely monitoring devices wirelessly, (ii) allow remotely controlling devices wirelessly, (iii) include GPS capability, (iv) allow taking measurements from multiple locations, (v) be easily updated as needed, and/or (vi) provide separate sensor and reader units.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which:

FIG. 1 is a diagram illustrating a system in accordance with an embodiment of the present invention;

FIG. 2 is a diagram illustrating an example operation of a reader and a sensor in accordance with an embodiment of the present invention;

FIG. 3 is a diagram illustrating an example implementation of a sensor of FIG. 1;

FIG. 4 is a diagram illustrating an example RF detector module of FIG. 3;

FIG. 5 is a diagram illustrating an example substrate attenuator and associated components of FIG. 4;

FIG. 6 is a diagram illustrating an example signal processing module of FIG. 3;

FIG. 7 is a diagram illustrating an example implementation of the signal processing module of FIG. 6;

FIG. 8 is a diagram illustrating an example look up table in accordance with an embodiment of the present invention;

FIG. 9 is a graph illustrating example power transfer curves for the RF detector of FIG. 4;

FIG. 10 is a diagram illustrating a carrying case for components of a system in accordance with an embodiment of the present invention; and

FIG. 11 is a flow diagram illustrating an example process in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a diagram is shown illustrating a system 100 in accordance with a preferred embodiment of the present invention. In one example, the system 100 may include a portable power meter comprising handheld reader and remote sensor units that use wireless technology to transmit measurement data from one unit to the other. Instead of building a read-out display into a main power head which contributes to the bulk of conventional portable power meters, the power meter, in accordance with an embodiment of the present invention, is split up into the remote sensor (or power head) unit and the handheld reader (or display) unit that communicate using a wireless protocol (e.g., Bluetooth, WLAN, ZigBee, etc.). Both components may be stored in and kept constantly charged by a carrying case that contains an internal rechargeable battery (described below in connection with FIG. 10). The power meter implemented in accordance with an embodiment of the present invention may achieve the same level of accuracy of conventional countertop models. The accuracy and portability of the system 100 generally guarantee ease-of-use, for example, in a laboratory setting or atop a radio tower.

In one example, the system 100 may comprise one or more handheld units 102 a-102 n and one or more remote sensor units (or monitors) 104 a-104 n. In one example, a handheld unit 102 a may be implemented as a dedicated reader. In another example, a handheld unit 102 b may be implemented as a personal computing device (e.g., cellular telephone, smart phone, tablet, PDA, etc.) configured through software (e.g., an application program or “APP”) to perform as a reader. In one example, the remote sensor units 104 a-104 n may be configured for connection to various types of communication equipment. For example, one or more of the remote sensor units 104 a-104 n may be implemented with a type “N” male adapter 106. In another example, one or more of the remote sensor units 104 a-104 n may be implemented with a type SMA female adapter 108. However, any other appropriate adapters for connecting to a particular system to be monitored may be implemented accordingly to meet the design criteria of a particular implementation. The remote sensor units 104 a-104 n are generally implemented as self-contained, calibrated sensor/processor/wireless transceiver modules.

In one example, the handheld unit 102 a may comprise a display 110 and a number of controls (e.g., switches, buttons, etc.) 112-120. In one example, the control 112 may be centered beneath the display 110. In one example, the control 112 may be configured as a power button. In another example, the control 112 may be configured to initiate a read operation. However, other functions may be implemented to meet the design criteria of a particular implementation. The controls 114 and 116 may be placed adjacent to one another and configured to provide complementary actions (e.g., scroll up, scroll down, etc.). The controls 118 and 120 may also be located adjacent to one another and similarly assigned complementary functions (e.g., scroll left, scroll right, etc.). The controls 114-120 may also be configured for selecting remote sensor units to be read by the handheld unit 102 a. In another example, the display 110 and controls 112-120 may also be realized as areas of a touch screen 122 of the device 102 b.

The system 100 may implement a wireless interface between the remote sensor units 104 a-104 n and the handheld (or display) units 102 a-102 n. The remote sensor units 104 a-104 n may be configured to transmit to any receiver compliant with the wireless protocol implemented by the sensor units. In one example, each remote sensor unit 104 a-104 n may have an individual MAC ID that may be used to identify the source of power readings and provide secure communications. In one example, the handheld units 102 a-102 n may be configured to maintain communications with multiple sensor units. For example, the controls on the handheld units 102 a-102 n may be used to switch between multiple remote sensor units. In one example, the handheld units 102 a-102 n may be configured to scan and pair to any available remote sensor units 104 a-104 n. Pairing to the remote sensor units 104 a-104 n may be performed one sensor at a time. In one example, the handheld units 102 a-102 n may be configured to display only a predetermined number of nearer remote sensor units. The remote sensor units 104 a-104 n may incorporate, in one example, a GPS (global positioning system) puck to provide location and time reference information (e.g., useful in cloud monitoring). In one example, the handheld units 102 a-102 n may be configured to display readings in alphanumeric format. However, other formats (e.g., graphic, oscilloscope, etc.) may be implemented to meet the design criteria of a particular implementation.

In one example, the remote sensor units 104 a-104 n may be calibrated using a 50 MHz power reference. Each of the remote sensor units 104 a-104 n generally stores a respective calibration table in non-volatile memory (e.g., Flash, EEPROM, etc.). Each of the remote sensor units 104 a-104 n may be re-calibrated and the table updated as needed (e.g., yearly, after repair due to damage, etc.). A threshold may be implemented for each of the remote sensor units 104 a-104 n to monitor a condition (e.g., impedance) of an integrated RF (radio frequency) detector (e.g., diode). Each of the remote sensor units 104 a-104 n may be configured to recommend re-calibration based on the threshold.

The system 100 may have many applications, including but not limited to testing cellular infrastructure equipment and WLAN (wireless local area network) devices, and allowing for the easy installation and maintenance of business communication systems. For example, the remote sensor units 104 a-104 n may be connected to the communication systems in hard to reach areas (e.g., on a cell tower, in a closed cabinet, etc.) and readings taken remotely (e.g., on the ground, outside the cabinet, etc.) from the remote sensors 104 a-104 n using one of the handheld units 102 a-102 n.

Referring to FIG. 2, a diagram is shown illustrating an example operation of the system 100. In one example, a remote sensor unit 104 i may comprise a block (or circuit) 150, a block (or circuit) 152, a block (or circuit) 154, a block (or circuit) 156, a block (or circuit) 158, a block (or circuit) 160, and a block (or circuit) 162. The block 150 may be implemented as a peak detector. The block 152 may be implemented as a diode device. The block 154 may be implemented as an analog-to-digital converter (ADC). The block 156 may be implemented as a processor. The block 158 may be implemented as a temperature module. The block 160 may be implemented as a memory. The block 162 may be implemented as a transceiver (TX/RX) module. In one example, the blocks 150-154 may be implemented as a first (analog) module and the blocks 156-162 may be implemented as a second (digital) module. The blocks 150-162 may be connected using conventional techniques.

In one example, a microwave (GHz) signal 180 may be sent through the remote sensor unit 104 i. The microwave signal 180 may initially be passed through the peak detector 150. An output of the peak detector 150 generally presents a signal representing the high frequency peak power (W) of the microwave signal 180. The output of the peak detector 150 may be present to a first terminal (or input) of the diode device 152. A second terminal (or output) of the diode device 152 may present a signal to the analog-to-digital converter 154. The analog-to-digital converter 154 may convert the output of the diode device 152 to the digital domain so that the processor 156 may transmit information (e.g., power level, etc.) regarding the digitized microwave signal via a wireless link 190 to the handheld display unit 102, where a user may read the information (e.g., power measurement, etc.).

The processor 156 is generally configured (e.g., through software, firmware, microcode, hardwiring, etc.) to generate the information regarding the digitized microwave signal. In one example, the processor 156 may generate the information using, for example, data for temperature compensation from the temperature module 158 and conversion (or calibration) tables stored in the memory 160. The information regarding the digitized microwave signal may be transmitted to the handheld unit 102 using the transceiver module 162. In one example, the memory 160 may be configured to store a three-dimensional lookup table containing calibration information for the particular remote sensor (or power head) unit 104 i.

Referring to FIG. 3, a diagram of remote sensor unit 104 is shown illustrating an example implementation of a remote sensor unit of FIG. 1. In one example, the remote sensor unit may comprise an RF detector module 200 and a signal processing module 202. An output of the RF detector module 200 may be connected to the signal processing module 202 using conventional techniques (e.g., soldering, a connector, surface mounting, etc.). The RF signal to be measured may be presented to the RF detector 200 through a connector attached to an input of the RF detector module 200.

Referring to FIG. 4, a diagram is shown illustrating a circuit diagram (a), a top view (b), and a side view (c) of an example implementation of the RF detector module 200 of FIG. 3. In one example, a zero bias Schottky diode detector (e.g., part number EZM0126PM1 manufactured by Eclipse Microwave of San Jose, Calif.) may be used to implement the RF detector module 200. In one example, the RF detector module 200 may comprise an input pin (or lead) 204, an output pin (or lead) 206, a match attenuator 210, and a capacitor 212. The pin 204 may be connected to an input of the match attenuator 210 using, in one example, a gold mesh. An output of the match attenuator 210 may be connected to a first terminal of the capacitor 212 using, in one example, a 0.7 mil gold wire. A second terminal of the capacitor 212 may be connected to the output pin 206 using, in one example, a 0.7 mil gold wire. The wire between the second terminal of the capacitor 212 and the output pin 206 may be held in place using a non-conductive epoxy stake 214.

In one example, a detector circuit of RF detector module 200 may comprise a first resistor (R1), a second resistor (R2), a third resistor (R3), a first capacitor (C1), a second capacitor (C2), and the zero bias Schottky diode (D1). The components may be implemented as part of the match attenuator 210. In another example, an optional second diode (D2) and third capacitor (C3) may also be implemented.

Referring to FIG. 5, a diagram of the match attenuator 210 of FIG. 4 is shown illustrating an example implementation. In one example, the match attenuator 210 may comprise a substrate attenuator and associated components implementing the detector circuit of FIG. 4. In one example, the substrate attenuator may be implemented comprising a first metal portion 220, a second metal portion 222, a third metal portion 224, a fourth metal portion 226, and a fifth metal portion 228. The metal portions 220 and 222 may be connect to a second substrate (e.g., a ground plane) using plated-through vias 230 and 232, respectively. The metal portion 224 may be connected to the metal portion 220 through a resistor R4 and a 0.7 mil gold wire. The metal portion 224 may also be connected to the metal portion 222 through a resistor R5 and a 0.7 mil gold wire. The metal portion 224 may be connected further to the metal portion 226 through a capacitor 240 and a gold wire mesh. The metal portion 226 may also be connected to (i) the metal portion 220 through a resistor R6 and a 0.7 mil gold wire, (ii) the metal portion 222 through a resistor R7 and a 0.7 mil gold wire, and (iii) the metal portion 228 through a resistor R8. The metal portion 228 may be connected to the metal portion 222 through a diode D1 and a capacitor 242.

In one example, the capacitor 240 may be implemented as a 100 pf surface mount capacitor. In one example, the capacitor 242 may be implemented as a 470 pf surface mount capacitor. The resistors R4, R5, R6, and R7 may be implemented, in one example, as 100 ohm, 5% tolerance surface mount resistors. The resistor R8 may be implemented, in one example, as a 50 ohm, 5% tolerance surface mount resistor. The resistors R4 and R5 generally correspond with the resistor R1 of FIG. 4. The resistors R6 and R7 generally correspond to the resistor R2 of FIG. 4. The resistor R8 generally corresponds to the resistor R3 of FIG. 4. The capacitors 240 and 242 generally correspond to the capacitors C1 and C2, respectively, of FIG. 4. In one example, the substrate attenuator may be formed on a 0.015 inch thick polished alumina substrate comprising 99.6% Al₂O₃. In one example, the substrate attenuator may have a finish of 250±50 angstroms TiW and 100UIN type Gold on both sides.

Referring to FIG. 6, a diagram is shown illustrating an example implementation of the signal processing module 202 of FIG. 3. In one example, the signal processing module 202 may comprise a circuit (or module) 250, a circuit (or module) 252, and a circuit (or module) 254. The circuit 250 may be implemented, in one example, as a video amplifier with autorange. The circuit 252 may be implemented, in one example, as a IEEE 802.15.4/ZigBee planar inverted F antenna (PIFA) module. However, other signal processing and wireless transceiver modules may be implemented accordingly to meet the design criteria of a particular implementation. In one example, the circuit 252 may be implemented using an MD100A ZigBee PIFA module available from Aveslink Technology, Inc. of San Jose, Calif. The circuit 254 may implement an extended memory for the circuit 252. The signal processing module 202 may also include a USB connector, which may be used to communicate with the circuit 252 and/or charge batteries associated with the remote sensor 104.

Referring to FIG. 7, a diagram is shown illustrating an example implementation of the module 252 of FIG. 6. In one example, the module 252 may comprise a circuit (or module) 260 and a circuit (or module) 262. The circuit 260 may be implemented, in one example, as a processing module. In one example, the circuit 260 may be implemented as a JN5139 chip available from Aveslink Technology, Inc. of San Jose, Calif. The circuit 262 may be implemented, in one example, as a serial flash memory. The module 252 may also include a crystal 264 and PIFA module 266. Optionally, the PIFA module 266 may be replaced with an interface to an external antenna. In one example, the optional interface may comprise a connector and a balun. In another example, the interface may also include a power amplifier (PA) and/or low noise amplifier (LNA).

In one example, the circuit 260 may comprise a processor (e.g., a RISC CPU), memory (e.g., random access memory (RAM), read only memory (ROM), etc.), a radio transceiver (e.g., 2.4 GHz), a modem (e.g., O-QPSK, etc.), an IEEE 802.15.4 MAC accelerator, an encryption accelerator (e.g., 128-bit AES, etc.), a serial peripheral interface (SPI), and a 2-wire serial interface (e.g., USB). The circuit 260 may also comprise one or more timers, one or more universal asynchronous receiver transmitters (UARTs), one or more 12-bit analog-to-digital converters (ADCs) and comparators, one or more 11-bit digital-to-analog converters (DACs), and a temperature sensor. The components of the circuit 260 may be connected by one or more busses. The circuit 260 may also comprise power management circuitry.

Referring to FIG. 8, a diagram of a table 290 is shown illustrating an example power lookup table (LUT) in accordance with an embodiment of the present invention. In one example, the table 290 may comprise a number of frequency data points F0, . . . , FN, a number of voltage data points V0, . . . , VN for each frequency F0, . . . , FN, and a number of power data points P0, . . . , PN for each frequency F0, . . . , FN. The table 290 may be configured to relate a voltage reading to a respective power reading for every frequency Fi. The size of the table 290 is generally only limited by the amount of memory (e.g., Flash, etc.) available.

Referring to FIG. 9, a graph 300 is shown illustrating example power transfer curves 302. In one example, the processor 156 may be configured to generate additional data values using the table stored in the remote sensor unit. For example, if a measurement from the ADC 154 falls between two frequency data points, the processor 156 may be configured to determined the correct frequency using, for example, straight-line interpolation or extrapolation. Similarly, if a voltage measurement falls between two points in the power table, the processor may be configured to take a slope of a corresponding one of the power transfer curves 302 to calculate the correct power measurement. Thus, the processor 156 may create a pseudo table for in-between frequencies based on the table stored in the remote sensor unit (e.g., in the memory 160). The power transfer curves 302 for the diode device are generally very predictable, so a lot of points are not necessary. In one example, 40 points may be used to calibrate the remote sensor unit 104 i (e.g., 1 dB steps from −30 to +10 dBm). In one example, the points may be calculated using one of the curves 302 and the following equations:

P2−P1=10 log [V2/V1], below −17 dBm;

and 18 log to 20 log above −17 dBm.

Referring to FIG. 10, a diagram is shown illustrating various components of a power meter system in accordance with an example embodiment of the present invention. In one example, a carrying case 400 may be configured to house the system 100 when the system 100 is not in use. In one example, the carrying case may provide space for the handheld unit 102, a number of remote sensor units 104 a-104 n, a power reference 402 for calibrating the remote sensor units 104 a-104 n, a USB charger 404, and a battery pack 406. The handheld unit 102 and the remote sensor units 104 a-104 n may be implemented with rechargeable batteries. The rechargeable batteries of the handheld unit 102 and the remote sensor units 104 a-104 n may be maintained in a charged condition using the USB charger 404 and/or the battery pack 406 in the carrying case 400. In one example, the internal battery pack 406 may be implemented as a 6-hour USB rechargeable battery, keeping both batteries of each separate unit constantly charged. The carrying case 400 may also include a shoulder or belt strap 408 for ease of carrying.

Referring to FIG. 11, a flow diagram is shown illustrating a power reading process 500 in accordance with another example embodiment of the present invention. In one example, the process (or method) 500 may comprise a step (or state) 502, a step (or state) 504, a step (or state) 506, a step (or state) 508, a step (or state) 510, a step (or state) 512, a step (or state) 514, a step (or state) 516, a step (or state) 518, a step (or state) 520, and a step (or state) 522. In the step 502, a frequency at which the measurement is being made may be input. In one example, the particular frequency may be entered by the user. For example, the handheld unit may implement a user interface that allows the user to scroll through and select frequencies at which measurements are made. When the frequency has been input, the process 500 may move to the step 504 where a frequency table is checked for the frequency that was input. The process 500 then moves to the step 506. In the step 506, a determination is made whether the frequency that was input in the step 502 is in the table checked in the step 504. When the frequency was not in the table, the process 500 moves to the step 508 and generates a frequency data point using two known frequency data points and library formulas 510. In one example, the process 500 may generate the new data point through straight-line interpolation or extrapolation. When the new frequency data has been generated or the frequency that was input in the step 502 was in the table, the process 500 moves to the step 512.

In the step 512, the process 500 may measure the voltage representing the microwave power level (e.g., reading the output of the ADC 154). When the voltage level has been measured, the process 500 may move to the step 514, where a power table is checked for the voltage that was measured. The process 500 then moves to the step 516. In the step 516, a determination is made whether the voltage that was measured in the step 512 is in the power table checked in the step 514. When the voltage was not in the power table, the process 500 moves to the step 518 and generates a power data point using two known power data points and library formulas 520. In one example, the process 500 may generate the new power data point through straight-line interpolation or extrapolation. When the new power data point has been generated or the voltage that was measured in the step 512 was in the power table, the process 500 moves to the step 522. In the step 522, the power is read and displayed or transmitted.

The functions performed by the diagram of FIG. 11 may be implemented using one or more of a conventional general purpose processor, digital computer, microprocessor, microcontroller, RISC (reduced instruction set computer) processor, CISC (complex instruction set computer) processor, SIMD (single instruction multiple data) processor, signal processor, central processing unit (CPU), arithmetic logic unit (ALU), video digital signal processor (VDSP) and/or similar computational machines, programmed according to the teachings of the present specification, as will be apparent to those skilled in the relevant art(s). Appropriate software, firmware, coding, routines, instructions, opcodes, microcode, and/or program modules may readily be prepared by skilled programmers based on the teachings of the present disclosure, as will also be apparent to those skilled in the relevant art(s). The software is generally executed from a medium or several media by one or more of the processors of the machine implementation.

The present invention may also be implemented by the preparation of ASICs (application specific integrated circuits), Platform ASICs, FPGAs (field programmable gate arrays), PLDs (programmable logic devices), CPLDs (complex programmable logic device), sea-of-gates, RFICs (radio frequency integrated circuits), ASSPs (application specific standard products), one or more monolithic integrated circuits, one or more chips or die arranged as flip-chip modules and/or multi-chip modules or by interconnecting an appropriate network of conventional component circuits, as is described herein, modifications of which will be readily apparent to those skilled in the art(s).

The present invention thus may also include a computer product which may be a storage medium or media and/or a transmission medium or media including instructions which may be used to program a machine to perform one or more processes or methods in accordance with the present invention. Execution of instructions contained in the computer product by the machine, along with operations of surrounding circuitry, may transform input data into one or more files on the storage medium and/or one or more output signals representative of a physical object or substance, such as an audio and/or visual depiction. The storage medium may include, but is not limited to, any type of disk including floppy disk, hard drive, magnetic disk, optical disk, CD-ROM, DVD and magneto-optical disks and circuits such as ROMs (read-only memories), RAMs (random access memories), EPROMs (erasable programmable ROMs), EEPROMs (electrically erasable programmable ROMs), UVPROM (ultra-violet erasable programmable ROMs), Flash memory, magnetic cards, optical cards, and/or any type of media suitable for storing electronic instructions.

The elements of the invention may form part or all of one or more devices, units, components, systems, machines and/or apparatuses. The devices may include, but are not limited to, servers, workstations, storage array controllers, storage systems, personal computers, laptop computers, notebook computers, palm computers, personal digital assistants, portable electronic devices, battery powered devices, set-top boxes, encoders, decoders, transcoders, compressors, decompressors, pre-processors, post-processors, transmitters, receivers, transceivers, cipher circuits, cellular telephones, digital cameras, positioning and/or navigation systems, medical equipment, heads-up displays, wireless devices, audio recording, audio storage and/or audio playback devices, video recording, video storage and/or video playback devices, game platforms, peripherals and/or multi-chip modules. Those skilled in the relevant art(s) would understand that the elements of the invention may be implemented in other types of devices to meet the criteria of a particular application.

While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention. 

1. A remote radio frequency power sensing unit comprising: a first module configured to generate an analog signal representative of a power level of a radio frequency (RF) signal; and a second module configured to (i) receive a particular frequency of a plurality of frequencies over a wireless communication channel from a device, (ii) digitize said analog signal to generate a value that conveys a magnitude of said power level of said RF signal, (iii) convert said value into a digital signal communicating said power level based on said particular frequency indexed into a table and (iv) transmit said digital signal communicating said power level over said wireless communication channel to said device.
 2. The remote radio frequency power sensing unit according to claim 1, wherein (i) said remote radio frequency power sensing unit is part of a power monitoring system and (ii) said particular frequency selected by a user of said device.
 3. The remote radio frequency power sensing unit according to claim 1, wherein said remote radio frequency power sensing unit is configured to update said table when connected to a calibration module configured to calibrate said remote radio frequency power sensing unit using a radio frequency power reference.
 4. The remote radio frequency power sensing unit according to claim 1, wherein said remote radio frequency power sensing unit is configured to be uniquely identified to said device.
 5. The remote radio frequency power sensing unit according to claim 1, wherein said second module is further configured to interpolate a data point in said table that corresponds to said particular frequency if said particular frequency falls between a plurality of indices of said table.
 6. The remote radio frequency power sensing unit according to claim 5, wherein said data point is interpolated from at least two other data points in said table corresponding to at least two of said indices above and below said particular frequency.
 7. The remote radio frequency power sensing unit according to claim 1, wherein said device comprises a handheld reader configured to (i) receive said digital signal communicating said power level over said wireless communication channel and (ii) display said power level of said RF signal.
 8. The remote radio frequency power sensing unit according to claim 1, wherein said table compensates for a temperature of said first module.
 9. A method of making remote radio frequency power measurements comprising: receiving a radio frequency (RF) signal at a circuit; generating an analog signal representative of a power level of said RF signal; receiving a particular frequency of a plurality of frequencies over a wireless communication channel from a device; digitizing said analog signal to generate a value that conveys a magnitude of said power level of said RF signal; converting said value into a digital signal communicating said power level based on said particular frequency indexed into a table; and transmitting said digital signal communicating said power level over said wireless communication channel to said device.
 10. The method according to claim 9, wherein (i) said circuit is part of a power monitoring system and (ii) said particular frequency selected by a user of said device.
 11. The method according to claim 9, further comprising: updating said table with a calibration module having a radio frequency power reference.
 12. The method according to claim 9, further comprising: uniquely identifying said circuit to said device.
 13. The method according to claim 9, further comprising: interpolating a data point in said table that corresponds to said particular frequency if said particular frequency falls between a plurality of indices of said table.
 14. The method according to claim 13, wherein said data point is interpolated from at least two other data points in said table corresponding to at least two of said indices above and below said particular frequency.
 15. The method according to claim 9, further comprising: receive said digital signal communicating said power level at said device over said wireless communication channel; and displaying said power level of said RF signal to a user of said device.
 16. The method according to claim 9, wherein said table compensates for a temperature of said circuit.
 17. A power monitoring system comprising: at least one remote radio frequency power sensing unit configured to (i) generate an analog signal representative of a power level of a radio frequency (RF) signal, (ii) receive a particular frequency of a plurality of frequencies over a wireless communication channel, (iii) digitize said analog signal to generate a value that conveys a magnitude of said power level of said RF signal, (iv) convert said value into a digital signal communicating said power level based on said particular frequency indexed into a table and (v) transmit said digital signal communicating said power level over said wireless communication channel; and a handheld reader configured to (i) transmit said particular frequency to said at least one remote radio frequency power sensing unit over said wireless communication channel, (ii) receive said digital signal communicating said power level over said wireless communication channel and (iii) display said power level of said RF signal in a user-understandable format.
 18. The power monitoring system according to claim 17, wherein said at least one remote radio frequency power sensing unit is further configured to interpolate a data point in said table that corresponds to said particular frequency if said particular frequency falls between a plurality of indices of said table.
 19. The power monitoring system according to claim 17, wherein said handheld reader is further configured to monitor a plurality of said remote radio frequency power sensing units.
 20. The power monitoring system according to claim 17, wherein said handheld reader is implemented as software on a personal computing device compliant with a wireless protocol of said wireless communication channel and selected from a group comprising (i) a cellular telephone, (ii) a smart phone, (iii) a tablet, (iv) a personal digital assistant, and (v) a computer-based device. 